For years, manufacturers have been weary of implementing robots simply because of safety concerns. Industrial robots are usually preferred in large manufacturing plants for activities like assembly line, dispensing, welding and even processing. These robots are automatically controlled, have multipurpose functions and are reprogrammable. However, with the use of heavy machinery, there is the added risk of injury, thus reducing the overall efficiency in a factory. Industry robots are space consuming, heavy and expensive, considering the fact that they require a safety cage or enclosure to avoid any contact, especially while co-working with humans.
According to the International Federation of Robotics, by 2018, around 1.3 mn industrial robots will be entering service in factories around the world. Since there is no escaping the fact that robots are the need of the hour, especially for sectors like automobile, food processing and manufacturing, collaborative robots or co-bots have been introduced, as they are easy to programme robotic arms meant to ease and simplify processes, and unlike conventional robots are mostly portable.
CO-BOTS AND RELATED STANDARDS
Collaborative robots (co-bots) are designed to work safely beside their human counterparts. They automate and streamline processes that are otherwise considered mundane and repetitive, in task-based industries. Due to their flexible nature and ability to work with people, collaborative robots are innovating in multiple industries like medical industry, food industry, fashion and television.
In a human-machine study conducted by MIT researchers at a BMW factory, it was shown that teams comprising of humans and robots were around 85 % more productive than teams made of either humans or robots working individually. Also, the cooperative process reduced human idle time by virtue of its pace-setting ability. They are also a more affordable option with minimum chances of any injury to the person, who is working alongside them.
To ensure this smooth integration of collaborative robots into the robotics space, there are new technical certifications that have been added to fulfil the risk assessment procedures that are considered standard for all industrial robots. A new technical specification has been introduced by the International Organization for Standardization (ISO) as a complementary document to support the previous ISO 10218 (Safety Requirements for Industrial Robots), which was only focused on industrial robots, as collaborative robots were still a new technology and not addressed in detail. This standard will elaborate on specific human-robot collaboration and the different requirements necessary to make sure the co-bot operate safely with humans in whatever industry it is used for.
The ISO/TS 15066 has been drafted by the ISO committee with members from 24 participating countries. With the ISO/TS 15066, the industry has received comprehensive guidelines, as in addition to design and risk assessment requirements, primarily to suppliers and integrators. It also presents a research study on 'injury level' data or pain thresholds versus robot speed, pressure and impact to specific body parts that has been developed by the University of Mainz, Germany. It is a document that provides supplemental and supporting information to the industrial robot safety standard ISO 102181 and ISO 10218-2 that was published in 2011, and is a good first step toward ensuring the safety of human workers in a collaborative robotic system.
To understand the need for this new specification, it is crucial to understand the kind of injuries that can occur while working with these robots to fully appreciate the need for ISO/TS 15066. There are two types of potentially hazardous contact – Quasi-static contact (clamping and pinching) and Transient contact (free space collision). Robot system-related hazards include end-effector and work piece hazard, fixture design, location of manually-controlled robot guiding devices, while application hazards include more process-specific hazards.
The ISO committee is using a grid, (1), to represent the individual body parts that will be exposed to a robot and has provided an exhaustive description of the desired force and pressure levels that will guide robot design and/ or integration. This data will offer different ways to analyse and prevent overshooting the threshold at impact. One of the ways to reduce impact is by designing the robot and robotic tools that are compliant and soft, which will reduce the force of the impact by their greater contact surface and by slowing deceleration during an impact. Another way to avoid reaching high part pain levels on impact to the body is to adjust the robot speed. By reducing the robot speed, you get smaller inertia, which means a smaller amount of force in case of impact.
When looking at ISO 10218, the different collaboration modes have only been mentioned – safety-rated monitored stop, hand guiding, speed and separation monitoring and power and force limiting. However, other than describing it, there are no details on the different requirements necessary to achieve those collaborative modes.
The ISO/TS 15066 is a frontward step to understanding what should go into a risk assessment and is a sign that collaborative robots are here to stay.